Auxiliary devices having cords, such as earphones, mice, keyboards, etc., are used in many electronic devices. In order to use more conveniently, cord winding modules have been increasingly provided in these auxiliary devices for receiving cords or signal wires. The cord winding module typically comprises a rotary wheel, a coil spring and a stopper structure. The cord is wound on the rotary wheel, and can be automatically retracted under the elastic restoring force of the coil spring. In the retracting process, the stopper structure can prevent the rotary wheel from rotating and stop the retracting of the cord, so that a suitable length of the cord that has not been retracted can be reserved.
The stopper structure comprises a stop button and an elastic support device. The elastic support device can provide an elastic force to the stop button, and the stopper structure automatically brakes the rotary wheel under the action of the elastic force. If the stop button is pressed, the rotary wheel will be released, and the retraction of the cord will be started again.
The stopper structures of the cord winding modules on the market are elastically supported by a compression spring or a torsion spring structure. Such a structure occupies a lot of space, which limits the miniaturization of the products.
For example, a Chinese invention patent titled “Accommodation Device” (Application No.: 201110267313.X) discloses a stopper structure of a cord winding module, in which a spring 415 is an elastic support device of a locking device 400. As shown in FIG. 4 and FIG. 5, the spring 415 is a compression spring and has a certain height. Thus, a second chamber is specially provided on a mounting portion 230 to accommodate the spring 415, and it occupies a large space.
A Chinese invention patent titled “Accommodation Device” (Application No. 201110417406.6) discloses a stopper structure of a cord winding module, in which an elastic member 420 is an elastic support device of a lock assembly 400. As shown in FIG. 4 and FIG. 5, the elastic member 420 is a compression spring and has a certain height. Thus, a fixing groove 444 is specially provided on a fixing member 440 to accommodate the elastic member 420, and it occupies a large space.
A Chinese utility model patent “Headphone Cord Winding-up Device, Headphone Assembly and Mobile Terminal” (Application No. 200920108072.2) discloses a stopper structure of a cord winding module, in which a hook spring 13 is an elastic support device of a hook plate 12. As shown in FIG. 1, the hook spring 13 is a torsion spring and has a certain height. Thus, a fixing slot is provided at the side of a base 8 to install the hook spring 13, and it also occupies a large space.